1. Field of the Invention
The present invention relates to analog filters. In particular, the present invention relates to analog filters suitable for use, for example, in mobile or telecommunications applications.
2. Discussion of the Related Art
From a fixed frequency sinusoidal source, an ideal poly-phase filter outputs equal-amplitude inphase (i.e., 0° and 180°) and quadrature (i.e., 90° and 270°) signals. However, in real implementations, due to source harmonics, circuit element mismatches, offset voltages and parasitic impedances, equal-amplitude inphase and quadrature output signals are difficult to achieve.